Approximate ages (in weeks) when teeth erupt in dogs and cats
Incisors 4-6 3-4 12-16 11-16
Canines 3-5 3-4 12-16 20-20
Premolars 5-6 5-6 16-20 16-20
Molars — — 16-24 20-24
The primary teeth start forming in utero and erupt between 3-12 weeks of age. The permanent crowns start forming at or shortly after birth and mineralization of the crowns (the part you can see) is complete by 11 weeks of age. Resorption and loss of the primary teeth and replacement by the permanent dentition occurs between 3-7 months of age in the dog and between 3-5 months of age in the cat. Once the crowns of the permanent teeth have erupted, root development continues for several months.